The present invention generally relates to an integrated disposable cartridge and more specifically, but not exclusively, concerns a cartridge manufactured in a cost-effective manner. Moreover, the integrated disposable includes a unique technique of transferring a fluid sample from a lancet to a test section.
The acquisition and testing of body fluids is useful for many purposes and continues to grow in importance for use in medical diagnosis and treatment, such as for diabetes, and in other diverse applications. In the medical field, it is desirable for lay operators to perform tests routinely, quickly, and reproducibly outside of a laboratory setting, with rapid results and a readout of the resulting test information. Testing can be performed on various body fluids and, for certain applications, is particularly related to the testing of blood and/or interstitial fluid. Performing home-based testing can be difficult for many patients, especially for patients with limited hand dexterity, such as the elderly or diabetics. For example, diabetics can sometimes experience numbness or tingling in their extremities, such as their hands, which can make self-testing difficult because they are unable to accurately position a test strip to collect the blood sample. In addition, wounds for diabetics tend to heal more slowly, and as a result, there is a desire to make incisions less invasive.
Recently, lancet integrated test strips or elements have been developed in which a test strip is integrated with a lancet or other piercing means so as to form a single disposable unit. While these integrated units have somewhat simplified the collection and testing of fluid samples, there are still a number of issues that need to be resolved before a commercial unit can be implemented. A few concerns for a multiple disposable unit include manufacturing the unit simply and inexpensively and positioning individual lancets and test strips in the commercial unit without damage to either the test strip or the lancet. Typically, a plurality of lancets and a plurality of test strips are each individually positioned in sealed compartments in a commercial unit. This process can be time consuming, expensive, and difficult to manufacture. Moreover, there is a possibility some of the lancets and/or test strips can be damaged while being positioned in the commercial unit.
Another concern of multiple disposable units disposed in a commercial unit is sterility of the lancets both initially and to maintain the sterility of the lancets until lancing the skin or tissue. As should be appreciated, sterilizing the lancets separately from the test sections eases the manufacturing process of a commercial unit. For example, the chemistry on the test sections is not disturbed by the separate sterilization of the lancets. After the lancets and test sections are assembled together, it is important to maintain the sterility of the lancets until lancing the skin or tissue to ensure an accurate testing event.
Yet another concern of multiple disposable units disposed in a commercial unit is the alignment of the lancet and test strip. Properly aligning the lancet and test strip ensures an accurate transfer of a body fluid sample from the lancet to the test strip. Moreover the proper alignment of the lancet and test strip reduces waste of the body fluid sample by accurately transferring the sample from the lancet to the test strip.
Another concern of users of multiple disposable units is the preference for smaller body fluid sample sizes that are used for testing, preferably a volume less than 1 microliter. Typically, a small body fluid sample requires a small penetration depth by the lancet which reduces the amount of pain for the user during lancing. Further, it is desirable that there is minimal or very little waste of body fluid from the lancet that is transferred to the test strip. Unnecessary waste of body fluid during the transfer of the body fluid from the lancet to the test strip can result in inaccurate test results or the need for larger body fluid samples to yield an accurate test result. There is a need for a multiple disposable unit that reduces the amount of pain for the user during lancing by using a lancet having a small penetration depth. Moreover there is a need for a multiple disposable unit that also efficiently transfers the small body fluid sample from the lancet to the test strip to eliminate any waste of body fluid.
A precise lancing profile for a lancet in an integrated disposable cartridge ensures an appropriate amount of a body fluid sample is collected during lancing the skin or tissue. A precise lancing profile for a lancet also ensures that an appropriate number of capillaries are cut during lancing the skin or tissue. For example, if too few capillaries are cut then the body fluid sample may not be large enough to yield accurate test results. If too many capillaries are cut then an overly large body fluid sample is collected and the user may experience a greater amount of pain than was necessary to obtain an adequate body fluid sample. Various configurations of the lancet and lancet entry have been used to attempt to solve these concerns. One configuration is a substantially straight lancet with a straight entry. One concern with a straight lancet having a straight entry is the deep penetration depth of the lancet which results in many capillaries being cut and a greater amount of pain for the user. Another configuration is a curved lancet with a rotational entry which can also result in an overly large wound and fluid sample and unnecessary pain for the user.
Thus, there is a need for improvement in this field.